Firearm Trigger

ABSTRACT

The bow portion of a firearm trigger is provided with a gripping surface disposed ordinarily for direct contact with a user&#39;s finger. The gripping surface receives pressure applied by the user to activate the trigger. A resilient coating overlies at least the gripping surface for direct contact with the user&#39;s finger.

RELATED APPLICATION

The priority of U.S. Provisional Application No. 61/841,605 filed Jul. 1, 2013 is claimed.

BACKGROUND

The present invention relates to triggers for firearms and more particularly to triggers offering benefits in the regimes of tactile comfort and improved friction for the finger, without sacrificing rigidity or ease of manufacture.

Firearms generally, including but not limited to rifles, pistols, revolvers, and shotguns, rely on a trigger, through the activation of which the user may discharge the weapon. Typically, triggers consist of a hook or blocking lever mechanism which holds a spring loaded hammer or firing pin under tension. The actual edge which engages the hammer or firing pin is referred to as a sear. Triggers also have a bow section, which protrudes outside the frame of the firearm. The bow is that portion of the trigger that is gripped by the user's finger and pulled, thereby enabling the firing mechanism to disengage the sear and release the hammer or firing pin at the desired moment, in order to discharge the weapon.

Triggers exist in multiple configurations. In a single stage trigger, a mechanism simply acts against a single preloaded spring. In a two stage trigger, a primary spring provides initial resistance, and a second spring applies additional resistance to the trigger in the last phase of travel before disengagement, thereby creating an increase in felt pressure on the trigger bow just prior to release of the hammer. In this manner the user is alerted to the impending discharge of the weapon. Other possible trigger mechanism designs involve the use of multiple levers in order to reduce the high force necessary to hold a hammer or firing pin retracted, so a light trigger pull can be applied by the user's finger to precisely release the hammer or firing pin at the right moment.

In all cases, shot accuracy depends on the shooter being able to control the exact moment the trigger releases the hammer or firing pin, which in turn causes the firearm to discharge, and to do so without upsetting the aim of the firearm. In the process of aiming, a firearm can easily be grasped or mounted, and presented to generally align in the direction of the target, but then refinement of position is needed to achieve the final precise alignment prior to discharge. During this refinement of position, shooters might shift their feet slightly, or hold their breath, or adjust their eye position relative to the sights. As these actions complete, a shooter will start to apply pressure to the trigger bow, perhaps pulling enough to take up initial slack, or to take up the first stage, but stopping at the second stage just prior to discharge. Then, when their positional refinement is complete, and the weapon is pointed at the target with precision, the trigger is pulled the last measure of travel, so the weapon discharges at the moment when the best possible alignment with the target is achieved. Perfect alignment with the target is a fleeting objective, for it is impossible for any shooter to bring a weapon to bear on a target and hold it perfectly still, so the shot could be delivered with no concern towards expedience. The aim of the weapon and the precise position of the shooter are always shifting, and in many cases, such as hunting or combat, the target is also not stationary. So the goal of an accurate shooter is to align, and pull the trigger right up to the brink of discharge, and hold it there while refining their aim, so that when the fleeting instant of perfect alignment presents itself, the shot can be discharged almost instantly.

A further need for accuracy is for the disengagement of the sear edges to be abrupt. Any motion of the trigger, against the force of the trigger spring, is work that is put into the weapon. This work input, while the shooter is trying to hold the weapon still, represents an upsetting and disruptive force which can move the weapon off its intended point of aim. For great accuracy, the transition from restraining the hammer or firing pin just prior to deciding to shoot, and releasing the hammer or firing pin, should be as crisp or abrupt as possible. To achieve this, the sear edges must be as sharp as possible.

The sear edge of the trigger, and the corresponding sear edge of the hammer or firing pin need to be strong in order to allow the above described crisp and predictable transition from the hammer or firing pin being restrained, to the hammer or firing pin being released. There is a pre load spring on the hammer or firing pin, which applies a force to the sear surfaces that are in contact, as the trigger restrains the movement of the hammer or firing pin. A load pressure can be calculated on the sear surface by taking the force of the hammer spring or firing pin spring, and dividing it by the sear contact area. As the trigger is pulled, and the sears begin to disengage, the contact area diminishes, while the force applied remains constant, so the pressure on the sear surfaces increases. As the trigger is pulled close to the release point of the hammer or firing pin, the sear contact area goes to zero, so the pressure applied at the sear edge will approach infinity. Obviously, no material will resist an infinite pressure, and once the pressure exceeds the yield point of the sear material, the sear tip will fail. So on a microscopic scale, the tips of a sear are never perfectly sharp, but will become round, with the radius of the rounding being driven partially by the yield point of the material of construction used in the sear edge. A material with a high yield strength is thus desirable in order to preserve sharp sear edges.

In addition, it is advantageous for the pull of the trigger by the shooter's finger, and the subsequent disengagement of the sear from the hammer or firing pin, to be as predictable and precise as possible. The user's finger must rely on the sensitivity of touch to keep careful control of the pull pressure. It is undesirable to pull the trigger to the release point too early, before being aligned on target. It is also undesirable to hold the trigger too far from the release point as it would require additional travel once the decision to fire is made and thereby upset the aim of the weapon. In order to maintain trigger finger sensitivity, the surface of the trigger bow should not be excessively cold or hot, nor should it have discernible sharp edges, which create pressure points on the finger, reducing blood flow and touch sensitivity.

It is also desirable for the finger to engage the trigger bow surface without slipping, as slippage may cause unpredictable movement of the trigger. Likewise, the trigger mechanism should be as rigid as possible, so that the movement of the trigger bow corresponds precisely to movement of the sear, without flexure or play in the trigger mechanism. In this manner, the shooter's ability to determine exactly where the brink of release is during the final moments of aiming is enhanced.

It is also important for the trigger mechanism to be reproduced at low cost and without undue complexity, which would make maintenance difficult.

Finally, it is important that a trigger be robust, so it can withstand the rigors of being used in an outdoor environment, or even combat, without risk of breaking.

Today, no trigger can satisfy all of these goals. Typically, triggers are made out of metal, steel being a common choice. A steel trigger is rigid, so movement of the trigger translates to predictable movement of the sear. A steel trigger will provide a sear edge with sufficient strength to maintain sharpness, thereby providing crisp release of the hammer. Steel is relatively inexpensive, and there are a variety of manufacturing methods, including casting and machining, allowing for easy production.

However, a steel trigger bow is unyielding to the touch, thereby reducing touch sensitivity and the ability to determine the precise amount of pressure which is being applied. In addition, the coefficient of friction of the finger against a steel trigger is relatively low, so the finger can easily slip on the bow surface. In the past, grooves or checkering have been added to the bow face to increase friction against the finger, but these enhancements can create sharp edges that can become uncomfortable if pressure is applied to the trigger is held for extended periods of time.

Plastic triggers have been developed. They were formed from hard plastic to maintain rigidity that translates to undelayed movement of the sear. Their hardness prevented these triggers from conforming to the finger, and thus did not improve tactile contact for the shooter. Further, plastic triggers lacked robustness, so in harsh or combat environments they were more easily broken than steel, rendering the weapon useless.

Accordingly, a trigger is sought which provides superior tactile contact to the finger with good anti-slip properties, yet retains the properties of being rigid, robust, offers high strength at the sear tips, and is easy to manufacture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of an M16 rifle;

FIG. 2 is a cut away view view of the M16 rifle shown in FIG. 1 and particularly illustrating the trigger and other firing mechanisms;

FIG. 3 is a side elevational view of an M1 rifle;

FIG. 4 is a side elevational view of a pistol;

FIG. 5 is a side elevational view of a revolver; and

FIG. 6 is a side elevational view of a trigger.

SUMMARY OF THE INVENTION

A firearm trigger has a bow portion provided with a gripping surface. The gripping surface is ordinarily disposed for direct contact with a user's finger. The gripping surface receives pressure applied by the user to activate the trigger. A resilient coating overlies at least the gripping surface for direct contact with the user's finger.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIGS. 1 and 2 illustrate an M16 style rifle, generally designated 10. The M16 may be equipped with a one or two stage trigger 12 having a user accessible trigger bow 14 projecting from a frame or lower receiver 16 and a single stage sear 18 disposed to releasably engage a hammer 20 disposed to drive a firing pin 22. The M16 is also equipped with a grip 24, a stock 26, a rear sight 28, an upper receiver 30, a front grip 32, a front sight 34, and a barrel 36.

FIG. 3 illustrates a rifle of the style of M1 Garand, generally designated 100. The M1 may be equipped with a trigger bow 114 extending outside a stock 126, a rear sight 128, a receiver 130, a forestock 132, a barrel 136, and a front sight 134.

FIG. 4 illustrates a pistol, generally designated 200. The pistol may be equipped with a trigger bow 214 extending outside a frame 216, a grip 224, a hammer (220), a rear sight 228, a slide 227, a front sight 234, and a barrel 236.

FIG. 5 illustrates a revolver, generally designated 300. The revolver may be equipped with the trigger bow 314 extending outside a frame 316, a grip 324, a hammer 320, a rear sight 328, a front sight 334, a barrel 336, and a cylinder 338.

As shown in FIG. 6, the bow portion 14 of a one or two stage trigger 12 may be substantially entirely covered by a coating 40 to provide comfort to the shooter's finger, while the hammer-engaging sear 18 is exposed, uncoated steel, offering high strength and rigidity. The coating 40 may be rubberized or other soft or padded polymer covering for gripping surfaces. One function of this coating is to allow a gripping surface 42 of the coating 40 to conform to the user's grip, thereby distributing the grip load and reducing the tactile grip pressure. Another function of the coating 40 is to increase the coefficient of friction between the grip surface 42 and the user's skin, thereby reducing the risk of the user's grip slipping on the trigger bow 14.

The coating 40 may be a rubber or polymer composition. The contact surface 42 between the finger and the trigger bow coating 40 can better distribute the load on the finger, increase friction and eliminate pressure points. All of the other attributes of a metal trigger—rigidity, ease of manufacture, and strength—may be preserved.

The coating 40 may be overmolded onto the trigger bow 14. It may be applied as a dip coating, as is often done on the handles of pliers and other hand tools. It may be applied as a powder coating, or it may be molded separately and then mounted on the trigger bow 14.

The rubber coating 40 may range from Extra Soft, in the range of 20 on the Shore OO scale, up to about 75 on the Shore D scale.

The coating 40 may be smooth, or it may be textured by molding in geometry, such as ridges, dimples, or bulges. It may also be textured through additives, for example by mixing sand in a dip coating. The coating may be expanded into an open or closed cell foam, adding more cushion.

The coating 40 may be insulative or at least characterized by low thermal conductivity within a range of 0-10 watts per meter·Kelvin (W/m·K), more preferably within a range of 0-5 W/m·K and most preferably within a range of 0-2 W/m·K. In this manner, the sensitive of the user's trigger finger may be substantially undiminished by a relative low or high temperature of the underlying trigger. 

1. In a firearm trigger, said trigger having a bow portion provided with a gripping surface disposed ordinarily for direct contact with a user's finger, said gripping surface receiving pressure applied by the user to activate the trigger, that improvement which comprises a resilient coating overlying at least the gripping surface for direct contact with the user's finger.
 2. The firearm trigger according to claim 1, wherein the resilient coating covers substantially the entire bow portion.
 3. The firearm trigger according to claim 1, wherein the resilient coating provides more friction with the user's finger than direct contact between the gripping surface and the user's finger.
 4. The firearm trigger according to claim 1, wherein the resilient coating distributes the pressure applied by the user's finger over a larger area of the gripping surface than direct contact between the gripping surface and the user's finger.
 5. The firearm trigger according to claim 1, wherein the resilient coating is composed of a rubberized polymer.
 6. The firearm trigger according to claim 1, wherein the firmness of the resilient coating is within a range of 20 on the Shore OO scale up to about 75 on the Shore D scale.
 7. The firearm trigger according to claim 1, therein the resilient coating has a smooth surface.
 8. The firearm trigger according to claim 1, wherein the resilient coating has a textured surface
 9. The firearm trigger according to claim 1, wherein the resilient coating has a thermal conductivity value within a range of 0-10 W/m·K.
 10. A covering for a firearm trigger, said trigger having a bow portion provided with a gripping surface disposed ordinarily for direct contact with a user's finger, said gripping surface receiving pressure applied by the user to activate the trigger, said covering comprising a resilient coating overlying at least the gripping surface for direct contact with the user's finger.
 11. In a firearm, said firearm having a trigger, said trigger having a bow portion provided with a gripping surface disposed ordinarily for direct contact with a user's finger, said gripping surface receiving pressure applied by the user to activate the trigger, that improvement which comprises a resilient coating overlying at least the gripping surface for direct contact with the user's finger. 